Edisoncarter is at it again! After the slew of San Andreas cheats he found, he is now working on uncovering cheats for Liberty City Stories. Although there is surely a lot more to come, here is what has been found so far:

HOLY SH!T!!! I had just given up on looking for cheats for LCS so I went here to see if there were any more updates before I go play and WAM!!! Oh man thats crazy...
But there's also three more:
Raise Wanted Level
L1, R1, SQUARE, L1, R1, TRIANGLE, L1, R1
Clear Wanted Level
L1, L1, TRIANGLE, R1, R1, X, SQUARE, CIRCLE
and
Cars Drive On Water
CIRCLE, X, DOWN, CIRCLE, X, UP, L1, L1